Background: Kaposi sarcoma–associated human herpesvirus (KSHV) encodes K-cyclin, a homologue of D-type cellular cyclins, which binds cyclin-dependent kinases to phosphorylate various substrates. ...K-cyclin/cdk phosphorylates a subset of substrates normally targeted by cyclins D, E, and A. We used cells naturally infected with KSHV to further characterize the biochemical features of K-cyclin. Methods: We used immunoprecipitation with K-cyclin antibodies to examine the association of K-cyclin with cdk2, cdk6, p21Cip1, and p27Kip1 proteins in BC3 cells. We separated populations of BC3 cells enriched in cells in G1, S, or G2/M phases by elutriation and measured K-cyclin protein and the kinase activity of K-cyclin/cdk6 complexes. The half-life of K-cyclin and cyclin D2 proteins was determined by blocking protein synthesis with cycloheximide and measuring proteins in cell lysates by western blot analysis. We fused the entire K-cyclin sequence to the carboxyl-terminal sequence of cellular cyclin D that contains the PEST degradation sequence to produce K-cyclin/D2 and transfected K-cyclin/D2 into K-cyclin–negative cells to investigate the effect of the PEST sequence on K-cyclin's stability. Results: Viral K-cyclin interacted with cyclin-dependent kinases cdk2, cdk4, and cdk6 and with the cyclin/cdk inhibitory proteins p21Cip1 and p27Kip1 in BC3 cell lysates. Unlike D-type cyclins, whose expression is cell cycle dependent, the level of K-cyclin was stable throughout the cell cycle, and the kinase associated with the K-cyclin/cdk6 complex was constitutively active. The half-life of K-cyclin (6.9 hours) was much longer than that of cellular cyclin D2 (0.6 hour) and that of K-cyclin/D2 (0.5 hour), probably because K-cyclin lacks the PEST degradation sequence present in D-type cyclins. Conclusion: The constitutive activation of K-cyclin/cdk complexes in KSHV-infected cells appears to result from the extended half-life of K-cyclin and may explain its role in Kaposi sarcoma.
Phys. Rev. D 107, 052008 (2023) This paper reports world averages of measurements of $b$-hadron, $c$-hadron,
and $\tau$-lepton properties obtained by the Heavy Flavour Averaging Group
using results ...available before April 2021. In rare cases, significant results
obtained several months later are also used. For the averaging, common input
parameters used in the various analyses are adjusted (rescaled) to common
values, and known correlations are taken into account. The averages include
branching fractions, lifetimes, neutral meson mixing parameters, CP violation
parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa
matrix elements.
Phys. Rev. Lett. 127 (2021) 211801 We report a measurement of the $D^0$ and $D^+$ lifetimes using $D^0\to
K^-\pi^+$ and $D^+\to K^-\pi^+\pi^+$ decays reconstructed in $e^+e^-\to
c\bar{c}$ data ...recorded by the Belle II experiment at the SuperKEKB
asymmetric-energy $e^+e^-$ collider. The data, collected at center-of-mass
energies at or near the $\Upsilon(4S)$ resonance, correspond to an integrated
luminosity of $72\,{\rm fb}^{-1}$. The results, $\tau(D^0) =
410.5\pm1.1\,{\rm(stat)}\pm0.8\,{\rm(syst.)}\,{\rm fs}$ and $\tau(D^+) =
1030.4\pm4.7\,{\rm(stat)}\pm3.1\,{\rm(syst.)}\,{\rm fs}$, are the most precise
to date and are consistent with previous determinations.
With the development of data-efficient reinforcement learning (RL) methods, a promising data-driven solution for optimal control of complex technical systems has become available. For the application ...of RL to a technical system, it is usually required to evaluate a policy before actually applying it to ensure it operates the system safely and within required performance bounds. In benchmark applications one can use the system dynamics directly to measure the policy quality. In real applications, however, this might be too expensive or even impossible. Being unable to evaluate the policy without using the actual system hinders the application of RL to autonomous controllers. As a first step toward agent self-assessment, we deal with discrete MDPs in this paper. We propose to use the value function along with its uncertainty to assess a policy's quality and show that, when dealing with an MDP estimated from observations, the value function itself can be misleading. We address this problem by determining the value function's uncertainty through uncertainty propagation and evaluate the approach using a number of benchmark applications.
Eur. Phys. J. C (2021) 81: 226 This paper reports world averages of measurements of $b$-hadron, $c$-hadron,
and $\tau$-lepton properties obtained by the Heavy Flavor Averaging Group using
results ...available through September 2018. In rare cases, significant results
obtained several months later are also used. For the averaging, common input
parameters used in the various analyses are adjusted (rescaled) to common
values, and known correlations are taken into account. The averages include
branching fractions, lifetimes, neutral meson mixing parameters, CP violation
parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa
matrix elements.
This paper reports world averages of measurements of \(b\)-hadron, \(c\)-hadron, and \(\tau\)-lepton properties obtained by the Heavy Flavour Averaging Group using results available before April ...2021. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa matrix elements.
This paper reports world averages of measurements of \(b\)-hadron, \(c\)-hadron, and \(\tau\)-lepton properties obtained by the Heavy Flavor Averaging Group using results available through September ...2018. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa matrix elements.
Eur. Phys. J. C77 (2017) 895 This article reports world averages of measurements of $b$-hadron,
$c$-hadron, and $\tau$-lepton properties obtained by the Heavy Flavor Averaging
Group using results ...available through summer 2016. For the averaging, common
input parameters used in the various analyses are adjusted (rescaled) to common
values, and known correlations are taken into account. The averages include
branching fractions, lifetimes, neutral meson mixing parameters, \CP~violation
parameters, parameters of semileptonic decays and CKM matrix elements.
A search for the flavor-changing neutral-current decay B$^+$→K$^+$$ν\overline{ν}$ is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data ...sample corresponds to an integrated luminosity of 63 fb$^{-1}$ collected at the $ϒ$(4S) resonance and a sample of 9 fb$^{-1}$ collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B$^+$→K$^+$$ν\overline{ν}$ decay, but also the inclusive properties of the other $B$ meson in the $ϒ$(4S)→$B\overline{B}$ event, to suppress the background from other $B$ meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B$^+$→K$^+$$ν\overline{ν}$ of 4.1×10$^{-5}$ is set at the 90% confidence level.
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